Recently, as an image recording material, recording materials used for the inkjet method, image recording materials for the thermal transfer, recording materials used for the electrophotographic method, halogenated silver photosensitive materials for transcription, printing inks, inks for recording pens, and the like are extensively used. Many of the recent recorded images are color images and a material for forming said color images is the mainstream. In addition, color filters are used in electronic parts such as LCD (liquid crystal display) or PDP (plasma display panel) for color and CCD (charge coupled device), where materials for forming color images are also used. In them, full color images are reproduced or recorded by so-called additive or subtractive color process, and coloring matters (dyes or pigments) of 3 primary colors are used as materials thereof. However, it is the case that there is no coloring matter having absorption characteristics which can provide preferable color reproduction areas and having sufficient fastnesses in various use conditions, so improvement of coloring matters is strongly required.
The inkjet recording method has been rapidly prevailing and further developing due to its low material cost, possibility of rapid recording, less noise in recording and also easiness of color recording. The inkjet recording method includes the continuous method of continuously flying ink droplets and the on-demand method of flying ink droplets responding to an image information signal, and the discharging method includes a method of discharging ink droplets by applying pressure with piezoelectric elements, a method of discharging ink droplets by generating bubbles in ink by heat, a method by using ultrasonic waves, a method of sucking and discharging ink droplets by electrostatic force, or the like. In addition, examples of the ink suitable for inkjet recording include water-based inks, oil-based inks, solid (melting-type) inks and the like.
The requirements for the coloring matter used for inks suitable for such inkjet recording include good solubility or dispersibility in solvents, ability of high density recording, good hue, good fastness to light, heat and active gases (oxidizing gas such as NOx and ozone, SOx and the like) in the environment, excellent durability against water and chemicals, good fixation to record-receiving materials in order not to bleed, excellent storage stability as an ink, no toxicity, and also inexpensive availability, and the like. In particular, strongly required is a cyan coloring matter which has a good cyan hue, is excellent in light fastness (durability against light), ozone fastness (durability against ozone gas) and moisture fastness (durability under high humidity), and causes no bronze phenomenon (also referred to as bronzing phenomenon). Bronze phenomenon means glare phenomenon that glossy paper has a metallic luster because coloring matter is aggregated on its surface due to association and aggregation of coloring matter, malabsorption of ink to the media, or the like. This phenomenon leads to inferiority in all respects such as glossiness, print quality and print density.
As a water-soluble cyan coloring matter used for inks suitable for inkjet recording, a phthalocyanine-based coloring matter and a triphenylmethane-based coloring matter are typical. The typical phthalocyanine-based coloring matter reported and used in the widest range includes phthalocyanine derivatives classified into the following A to H:
A: known phthalocyanine-based coloring matter such as Direct Blue 86, Direct Blue 87, Direct Blue 199, Acid Blue 249, Reactive Blue 71 or the like;
B: phthalocyanine-based coloring matter described in Patent Literatures 1 to 3 and the like (for example, a mixture of Cu—Pc—(SO3Na)m(SO2NH2)n:m+n=1 to 4);
C: phthalocyanine-based coloring matter described in Patent Literature 4 and the like (for example, Cu—Pc—(CO2H)m(CONR1R2)n:m+n=a number of 0 to 4);
D: phthalocyanine-based coloring matter described in Patent Literature 5 and the like (for example, Cu—Pc—(SO3H)m(SO2NR1R2)n:m+n=a number of 0 to 4, and m≠0);
E: phthalocyanine-based coloring matter described in Patent Literature 6 and the like (for example, Cu—Pc—(SO3H)l(SO2NH2)m(SO2NR1R2)n:l+m+n=a number of 0 to 4);
F: phthalocyanine-based coloring matter described in Patent Literature 7 and the like (for example, Cu—Pc—(SO2NR1R2)n:n=a number of 1 to 5);
G: phthalocyanine-based coloring matter described in Patent Literatures 8, 9 and 12 and the like (phthalocyanine compound in which the substitution position of the substituent is controlled and phthalocyanine-based coloring matter in which a substituent is introduced at the beta-position);H: benzo pyridoporphyrazine-based coloring matter having a pyridine ring and a benzene ring, described in Patent Literatures 10, 13 and 14, and the like.
The phthalocyanine-based coloring matter typified by Direct Blue 86 or Direct Blue 199 which are usually used widely at present has a characteristic of being excellent in light fastness compared with magenta coloring matters and yellow coloring matters which are generally known. The phthalocyanine-based coloring matter has a greenish hue under acidic conditions, whereby it is not very preferable as a cyan ink. Therefore, it is preferable that these coloring matters are used under neutral to alkaline conditions when used as a cyan ink. However, although the ink to be used is neutral to alkaline, the hue of a printed matter may be greatly changed when the record-receiving material to be used is an acidic paper.
In addition, when the phthalocyanine-based coloring matter is used as a cyan ink, the hue of a printed matter is discolored greenish and also color fading occurs due to oxidizing gases such as nitrogen oxide gas and ozone which are often concerned nowadays as an environmental problem, whereby the print density is concurrently reduced.
On the other hand, the triphenylmethane-based coloring matter has a good hue but is very inferior in light fastness, ozone fastness and moisture fastness.
From here on, when the application field of inkjet recording is widespread and inkjet recording is widely used in articles on exhibition for advertisement and the like, the coloring matter and the ink used there will be more and more strongly required to have a good hue and to be inexpensive, and further, in particular to have a good hue and to be excellent in light fastness, fastness to active gases in the environment (oxidizing gases such as NOx and ozone and in addition SOx, and the like) and moisture fastness because they will be more often exposed to light and active gases in the environment. However, it is difficult to develop a cyan coloring matter (for example, phthalocyanine-based coloring matter) and a cyan ink which satisfy these requirements at a high level. In the past, although phthalocyanine-based coloring matters to which fastness to active gases is imparted are disclosed in Patent Literatures 3, 8 to 12, and 14, and the like, a cyan coloring matter and a cyan ink have not yet been obtained which satisfy all the qualities such as hue, light fastness, ozone fastness, moisture fastness and no bronze phenomenon, and further which can be produced inexpensively. Therefore, the requirements of the market have not been sufficiently satisfied.
Patent Literature 1: JP S62-190273 A
Patent Literature 2: JP H7-138511 A
Patent Literature 3: JP 2002-105349 A
Patent Literature 4: JP H5-171085 A
Patent Literature 5: JP H10-140063 A
Patent Literature 6: JP H11-515048 A
Patent Literature 7: JP S59-22967 A
Patent Literature 8: JP 2000-303009 A
Patent Literature 9: JP 2002-249677 A
Patent Literature 10: JP 2003-34758 A
Patent Literature 11: JP 2002-80762 A
Patent Literature 12: WO 2004087815 A
Patent Literature 13: WO 2002034844 A
Patent Literature 14: JP 2004-75986 A